用户模拟角色类。实现在程序段内进行用户角色模拟。(以前收集的资料，原始出处当时没记，请作者谅解)

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  System.Runtime.InteropServices;
using  System.Security.Principal;

namespace  TY.Framework
{

     ///    用户模拟角色类。实现在程序段内进行用户角色模拟。 
     ///    <example><![CDATA[使用的时候在你要执行特殊操作的代码段前面这样写：   
     ///          IdentityImpersonation   identityImpersonation   =   new   IdentityImpersonation("administrator", "yourpassword","yourhostname");   
     ///          identityImpersonation.BeginImpersonate();//开始管理员扮演   
     ///          //你的特殊操作   
     ///          ..   
     ///          .   
     ///        identityImpersonation.StopImpersonate();   //结束扮演]]>
     ///    </example>
     ///   
     public   class  IdentityImpersonation
    {

        [DllImport( " advapi32.dll " , SetLastError  =   true )]
         public   static   extern   bool  LogonUser(String lpszUsername, String lpszDomain, String lpszPassword,  int  dwLogonType,  int  dwLogonProvider,  ref    IntPtr phToken);



        [DllImport( " advapi32.dll " , CharSet  =  CharSet.Auto, SetLastError  =   true )]
         public   extern   static   bool  DuplicateToken(IntPtr ExistingTokenHandle,  int  SECURITY_IMPERSONATION_LEVEL,  ref    IntPtr DuplicateTokenHandle);



        [DllImport( " kernel32.dll " , CharSet  =  CharSet.Auto)]
         public   extern   static   bool  CloseHandle(IntPtr handle);



         //    要模拟的用户的用户名、密码、域(机器名)   
         private  String _sImperUsername;

         private  String _sImperPassword;

         private  String _sImperDomain;

         //    记录模拟上下文   
         private  WindowsImpersonationContext _imperContext;

         private  IntPtr _adminToken;

         private  IntPtr _dupeToken;

         //    是否已停止模拟   
         private  Boolean _bClosed;




         ///   <summary>
         ///  构造函数
         ///   </summary>
         ///   <param name="impersonationUsername"> 所要模拟的用户的用户名 </param>
         ///   <param name="impersonationPassword"> 所要模拟的用户的密码 </param>
         ///   <param name="impersonationDomain"> 所要模拟的用户所在的域 </param>
         public  IdentityImpersonation(String impersonationUsername, String impersonationPassword, String impersonationDomain)
        {

            _sImperUsername  =  impersonationUsername;
            _sImperPassword  =  impersonationPassword;
            _sImperDomain  =  impersonationDomain;

            _adminToken  =  IntPtr.Zero;
            _dupeToken  =  IntPtr.Zero;
            _bClosed  =   true ;

        }



         ///   <summary>
         ///  析构函数
         ///   </summary>
         ~ IdentityImpersonation()
        {
             if  ( ! _bClosed)
            {
                StopImpersonate();
            }
        }



         ///   <summary>
         ///  开始身份角色模拟。   
         ///   </summary>
         ///   <returns></returns>


         public  Boolean BeginImpersonate()
        {
            Boolean bLogined  =  LogonUser(_sImperUsername, _sImperDomain, _sImperPassword,  2 ,  0 ,  ref    _adminToken);
             if  ( ! bLogined)
            {
                 return   false ;
            }
            Boolean bDuped  =  DuplicateToken(_adminToken,  2 ,  ref    _dupeToken);
             if  ( ! bDuped)
            {
                 return   false ;
            }

            WindowsIdentity fakeId  =   new  WindowsIdentity(_dupeToken);
            _imperContext  =  fakeId.Impersonate();
            _bClosed  =   false ;
             return   true ;

        }


         ///   <summary>
         ///  停止身分角色模拟。 
         ///   </summary>
         public   void  StopImpersonate()
        {
            _imperContext.Undo();
            CloseHandle(_dupeToken);
            CloseHandle(_adminToken);
            _bClosed  =   true ;

        }

    }
}